Left: If I'm not mistaken, this label would go on the side of the Proton Gun, above the two round side disks.Middle: This goes on the block on the underside of the Proton Pack which the blue and red tubes feed into (alternately there is a red warning label in this location on some props)Right: This appears to be a spare of the label that goes on the N-Filter.

This is a spare label for the one on the Gear Box, beneath the crank knob.

This may be a spare for the N-Filter, or possibly for the label on the side disc side of the Proton Gun... It's tricky to tell as the cropping obscures the size/location with the other labels on the sheet.

Red Label: This goes on the motherboard, towards the top (Just visible near the top of this photo).
White triangles: These are used exclusively on the Ghost Trap.

Looking at your Pack and Gun, here are a few observations for potential changes/modifications to potentially make in the future:

•The rear cyclinder: Although the Rear Cylinder has been reproduced in silver on the Spengler Legacy Kit and Spirit Halloween Proton Pack because this element on the Super Hero prop is silver, this element was originally black like the rest of the Proton Gun. In the 30+ years since it was originally build, the paint has flaked off of this element.
•The red side label: As far as I'm aware the label on the side of the Proton Gun is silver in all instances, rather than red. It is however the applicator's preference as to whether the label is placed upside down, or right-side up, as there is precedent for both:
•The Rear Instrument Bar label: The red label on the cover plate on the Proton Gun Rear Instrument Bar should have been placed a little further to the right, so that it sat underneath the barb with the green hose.
•The toggle switch decals: The decals for the toggle switches are currently swapped around, the decal with the diagonal line should have been placed beneath the upper switch, whilst the decal with the dot in the centre should have been placed beneath the lower switch.
•The Trigger Box push switch: The push switch on the Trigger Box should be black, rather than red.
•Cross head screws: It may be worth replacing some of the visible cross-head screws for cap-head screws for the hook on the Proton Gun, and hex socket countersunk screws on the gun hook, as those were the screws used on the screen-used props.
•The Legris straight fittings: Removing the blue plastic caps on the brass straight fittings will help make them look more accurate to the fittings used on the screen-used props.
•Misc Pack pneumatic tubes: replacing the thin red and yellow tubes/wires with a thicker stock will help improve their visual impact.
•The gray Legris elbows: These were a matte, or slightly shiny gray, rather than silver. They're only silver on the Spirit Halloween Pack because the people defining the colour scheme got it wrong.

I hope this doesn't come off as being entirely negative or picky, these are suggestions you could employ, but you can give them a pass if you're happy with the Pack as-is.

Looking at some screen used pack photos I noticed the screws on the side of the pack that is missing from the Anovos. Because the brackets on the Anovos are glassed in, the screws on my pack are only cosmetic.

I believe the lenses on the Proton Packs used in Ghostbusters and Ghostbusters II were clear, however a lot of folks (including yours truly) opt for frosted because, as Marcus noted, they help obscure the LEDs better - the frosted effect also helps spread the light.

As for mounting, some folks mount flashlight reflectors to the shell, and fix the LEDs to the reflectors:

Others (especially those who have LED clusters for each Cyclotron light) mount the lights to metal rigs which are attached to the motherboard, and hold the lights in the right location - which is an adaption of how it was done in the screen-used Packs:

An option might be, depending on if the depth allows for it, is too put something over the LEDs to diffuse them, while putting a clear lens on the pack to better replicate the movie packs and create the illusion you're using incandescent bulbs.